Pain in legs when sitting or standing

[sofa weight]

I am having fairly severe pain in my legs running the path of L5 and S1 whenever I sit for more than a minute or two, and whenever I stand in place for more than 4-5 minutes. If I am walking, it isn't so bad, and if I am lying flat, I am ok. I feel the pain mostly in the left leg and if the left leg is numbed up, then I feel it in the right leg, but not as bad as it is in the left leg. I have some numbness in my feet, and sometimes feel like I am walking in a water puddle. I don’t have any motor weakness, but my left knee feels a little week or at least unstable.
Because of this, I haven't been able to work for awhile because I work in an office and have to sit in a chair at my computer all day. MRIs have been normal.  I just had a bone scan done and the results were normal. I am wondering what could possibly be causing the pain in my legs when those tests are normal. I am scheduled to have a CT Myelogram done next week, but am apprehensive about having it done. Because all of the tests up to this point have been normal, aside from a nerve scan that showed a problem with the L5 nerve in both legs, I guess there isn't any other option to find the problem and fix it. I am just concerned that the CT Myelogram will be normal too and I’ll be stuck with no solution. The nerve scan showed a problem with the L5 in both legs, mostly in the left leg. I went to an orthopedic doctor for and he had me wear and SI belt for a couple of months. I wore the belt just like I was supposed to, but it didn’t seem to help.
I read that the piriformis muscle can cause the nerves to get pinched, but I didn't get pain from the test they said to try. My questions are: What can possibly be causing the problem with my legs, considering the results of the tests that I mentioned above. Also, are there any tests that would be good to run before the myelogram or if the myelogram doesn’t show a reason for the problem either? Can you tell me what can be causing the pain?

[ouch_i_hurt]

I have a very similar problem.  I have exteme pain in left leg when I sit or stand.  If I primarily rest (sit or lay) then I have very little pain.  However, a short trip to Wal-Mart, standing for 10 minutes and then attempting to sit and then stand is extremely painful!  I've been treated by 3 doctors thus far.  The first diagnosis was a pulled muscle, the second was a possible pinched nerve and low B12, third was a chiropractor with pinched nervec at L5 with bone on bone, spatulation, and low B12. Chiropractor is trying to adjust my vertabrae to relieve the pain.  I'm taking Lyrica and Medrol, plus Lorcet Plus when needed, but it's been 3 weeks and it's horrible.  I don't wont a neurosurgeon and have not been to a neurologist.  It's just in my mind it's not logical that it's a nerve problem that only causes pain after activity when I sit.  The walking isn't painfully and the standing after I sit is barable, but the sitting is deadly!   PS:  I've had a few B12 shots and am taking 2000mcg a day.

[sofa weight]

I do have borderline low b12, and all the bloodwork has been done including genetic testing for hereditary neuropathy. I would have had all of that in there if I wasn't limited to 2000 characters. I had to remove that part to fit it in. I get b12 injections biweekly for that. And peripheral neuropathy makes sense for numbness, but would peripheral neuropathy really explain having my legs feel so much pain so quickly just from sitting down? I don't have diabetes or any vascular problem. My thyroid is fine too. I said in the original post that I hvae seen 3 neurologists already. oh no, wait. I guess I had to cut that part out to fit into 2000 characters too. oh well.

[Kevin Pho, MD]

I agree with the workup thus far, and it has been comprehensive.  

Peripheral neuropathy can be considered, and evaluated with nerve conduction studies.  

Systemic causes can be evaluated with blood tests to exclude diabetes, thyroid disorders, or B12 deficiency.  

A referral to a neurologist should be considered to discuss these tests.

These options can be discussed with your personal physician.

Followup with your personal physician is essential.

This answer is not intended as and does not substitute for medical advice - the information presented is for patients education only. Please see your personal physician for further evaluation of your individual case.

Kevin, M.D.
www.kevinmd.com